Efforts to improve PV devices, particularly those devices that are integrated into building structures (e.g. photovoltaic sheathing elements, spacer pieces, edge pieces), to be used successfully, should satisfy a number of criteria. The PV device and the array as installed should be durable (e.g. long lasting, sealed against moisture and other environmental conditions) and protected from mechanical abuse over the desired lifetime of the product, preferably at least 10 years, more preferably at least 25 years. The device should be easily installed into the array of devices (e.g. installation similar to conventional roofing shingles or exterior wall coverings) or replaced (e.g. if damaged). It also should be designed to prevent, as much as possible, water from getting under the device and to the building surface that the device is affixed to.
To make this full package desirable to the consumer, and to gain wide acceptance in the marketplace, the system should be inexpensive to build and install. This may help facilitate lower generated cost of energy, making PV technology more competitive relative to other means of generating electricity.
Existing art systems for PV devices may allow for the device to be directly mounted to the building structure or they may fasten the devices to battens, channels or “rails” (“stand-offs)) above the building exterior (e.g. roof deck or exterior cladding). These systems may be complicated, typically do not install like conventional cladding materials (e.g. roofing shingles or siding) and, as a consequence, may be expensive to install. Also, they may not be visually appealing as they do not look like conventional building materials. “Stand-offs” to mount PV device every 2-4 feet may be required. Thus, installation cost can be as much or more as the cost of the article. They also may suffer from issues related to environmental conditions such as warping, fading and degradation of its physical properties. In addition when a PV device in an array goes bad replacement can be difficult and costly. In those embodiments where the PV device is directly attached to a roof or building replacement of a bad PV device may require removal of several of the devices for replacement. This can result in very high replacement costs.
Among the literature that can pertain to this technology include the following patent documents: U.S. Pat. Nos. 5,590,494; 7,455,508; 5,990,414; 7,682,363, all incorporated herein by reference for all purposes.